This invention is particularly applicable to the generating of selected predetermined curvatures on the faces of lens blanks although it can be used in generating curvatures on surfaces of any workpieces to be used for producing various articles. The surface generating tool may be a cutting tool, a grinding tool or various other tools which will produce the desired surface curvature as it is swung across the workpiece in contact with the surface thereof while the workpiece is simultaneously rotated about its own axis.
At the present time, it is customary to use ordinary lathes for producing spherical surfaces on plastic contact lenses. The lens blank is rotated about its axis and the usual cutting tool is swung about a fixed pivot in contact with the lens blank to impart the desired spherical curvature to the surface of the lens blank. This is accomplished by swinging the feed carriage which carries the cutting tool about its fixed pivot in the usual manner. There is a need for a lathe for generating an aspherical surface curvature on the lens blank so that the resulting contact lens will more properly fit the eyeball which is not spherical.